Preheat the oven to 350°F (175°C) and line an 9-inch loaf pan with baking paper, leaving an overhang for easy removal.
Zest 2–3 lemons and rub the zest into the sugar to release the oils.
In a large mixing bowl, combine the milk, lemon juice, vanilla extract, yogurt, and the lemon-sugar mixture. Stir until well blended.
Sift in the flour, baking powder, baking soda, and salt. Mix until the dry ingredients are fully incorporated into the wet mixture.
Add the melted butter and stir until smooth.
Toss the blueberries in a tablespoon of flour to prevent them from sinking, then gently fold them into the batter.
Pour the batter into the prepared loaf pan and use a knife to gently score a slit lengthwise down the center to help the loaf rise evenly as it bakes.
Bake for about 50 minutes if using fresh blueberries or 1 hour 5 minutes if using frozen blueberries, insert a toothpick n the center to check if it comes out clean. Baking time may vary slightly depending on your oven. Once baked, transfer the loaf to a wire rack to cool.